As a field get saturated one of the easiest ways to stand out is to take generalized tips from one field and apply them to another niche. Recently Rebecca mentioned this Recruitment SEO guide, and a friend of mine named Dave spotted this real estate marketing guide.
Some resources are niche specific while others are applicable to many industries. Ping Pong Pie (nice domain name) compiled a list of top social networking sites by category. The Zip Code Guy blog offers a 27 MB database of US cities, counties, and states which works great for local keyword generation for AdWords when used in combination with tools like Speed PPC.
More: continued here
